The efi_call() wrapper used to invoke EFI runtime services serves
a number of purposes:
- realign the stack to 16 bytes
- preserve FP register state
- translate from SysV to MS calling convention.
Preserving the FP register state is redundant in most cases, since
efi_call() is almost always used from within the scope of a pair of
kernel_fpu_begin()/_end() calls, with the exception of the early
call to SetVirtualAddressMap() and the SGI UV support code. So let's
add a pair of kernel_fpu_begin()/_end() calls there as well, and
remove the unnecessary code from the assembly implementation of
efi_call(), and only keep the pieces that deal with the stack
alignment and the ABI translation.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
arch/x86/platform/efi/efi_64.c | 4 +++
arch/x86/platform/efi/efi_stub_64.S | 36 ++------------------
arch/x86/platform/uv/bios_uv.c | 7 ++--
3 files changed, 11 insertions(+), 36 deletions(-)
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 03c2ed3c645c..3690df1d31c6 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -84,6 +84,7 @@ pgd_t * __init efi_call_phys_prolog(void)
if (!efi_enabled(EFI_OLD_MEMMAP)) {
efi_switch_mm(&efi_mm);
+ kernel_fpu_begin();
return efi_mm.pgd;
}
@@ -141,6 +142,7 @@ pgd_t * __init efi_call_phys_prolog(void)
}
__flush_tlb_all();
+ kernel_fpu_begin();
return save_pgd;
out:
efi_call_phys_epilog(save_pgd);
@@ -158,6 +160,8 @@ void __init efi_call_phys_epilog(pgd_t *save_pgd)
p4d_t *p4d;
pud_t *pud;
+ kernel_fpu_end();
+
if (!efi_enabled(EFI_OLD_MEMMAP)) {
efi_switch_mm(efi_scratch.prev_mm);
return;
diff --git a/arch/x86/platform/efi/efi_stub_64.S b/arch/x86/platform/efi/efi_stub_64.S
index b1d2313fe3bf..3e44d55ac730 100644
--- a/arch/x86/platform/efi/efi_stub_64.S
+++ b/arch/x86/platform/efi/efi_stub_64.S
@@ -8,41 +8,11 @@
*/
#include <linux/linkage.h>
-#include <asm/segment.h>
-#include <asm/msr.h>
-#include <asm/processor-flags.h>
-#include <asm/page_types.h>
-
-#define SAVE_XMM \
- mov %rsp, %rax; \
- subq $0x70, %rsp; \
- and $~0xf, %rsp; \
- mov %rax, (%rsp); \
- mov %cr0, %rax; \
- clts; \
- mov %rax, 0x8(%rsp); \
- movaps %xmm0, 0x60(%rsp); \
- movaps %xmm1, 0x50(%rsp); \
- movaps %xmm2, 0x40(%rsp); \
- movaps %xmm3, 0x30(%rsp); \
- movaps %xmm4, 0x20(%rsp); \
- movaps %xmm5, 0x10(%rsp)
-
-#define RESTORE_XMM \
- movaps 0x60(%rsp), %xmm0; \
- movaps 0x50(%rsp), %xmm1; \
- movaps 0x40(%rsp), %xmm2; \
- movaps 0x30(%rsp), %xmm3; \
- movaps 0x20(%rsp), %xmm4; \
- movaps 0x10(%rsp), %xmm5; \
- mov 0x8(%rsp), %rsi; \
- mov %rsi, %cr0; \
- mov (%rsp), %rsp
SYM_FUNC_START(efi_call)
pushq %rbp
movq %rsp, %rbp
- SAVE_XMM
+ and $~0xf, %rsp
mov 16(%rbp), %rax
subq $48, %rsp
mov %r9, 32(%rsp)
@@ -51,8 +21,6 @@ SYM_FUNC_START(efi_call)
mov %rcx, %r8
mov %rsi, %rcx
call *%rdi
- addq $48, %rsp
- RESTORE_XMM
- popq %rbp
+ leave
ret
SYM_FUNC_END(efi_call)
diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
index ece9cb9c1189..5c0e2eb5d87c 100644
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -34,10 +34,13 @@ static s64 __uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3,
* If EFI_OLD_MEMMAP is set, we need to fall back to using our old EFI
* callback method, which uses efi_call() directly, with the kernel page tables:
*/
- if (unlikely(efi_enabled(EFI_OLD_MEMMAP)))
+ if (unlikely(efi_enabled(EFI_OLD_MEMMAP))) {
+ kernel_fpu_begin();
ret = efi_call((void *)__va(tab->function), (u64)which, a1, a2, a3, a4, a5);
- else
+ kernel_fpu_end();
+ } else {
ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, a5);
+ }
return ret;
}
--
2.17.1
